JP2009235396A - Methacrylic polymer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a methacrylic polymer composition capable of obtaining a molding excellent in weatherability, flexibility, transparency and appearance. <P>SOLUTION: This methacrylic polymer composition contains, as a dispersion phase, a block copolymer B having a polymer block (a) comprising a repetition unit derived from an alkyl (meth)acrylate, and a polymer block (b) comprising a repetition unit derived from a conjugated diene compound, in a continuous phase comprising a methacrylic resin A having 50 mass% or more repetition unit derived from methyl methacrylate, and contains the block copolymer B of more than 80 pts.mass but 300 pts.mass or less based on 100 pts.mass methacrylic resin A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a methacrylic polymer composition capable of obtaining a molded article excellent in flexibility, hot water whitening resistance, transparency, and appearance (low roughness).

  Conventionally, typical soft resins include soft vinyl chloride resins and urethane resins. In particular, soft vinyl chloride resins are used in a wide range of applications such as desk mats and medical packs such as blood. However, soft vinyl chloride resins contain a large amount of plasticizers and anti-aging stabilizers for softening, and there are concerns about the effects of these additives on the human body in medical applications. In addition, the vinyl chloride resin is difficult to regenerate, and since it generates chlorine gas or the like during incineration, it is currently buried. Therefore, a flexible resin that can replace this is widely desired.

  On the other hand, a molded product of a methacrylic resin typified by polymethyl methacrylate is excellent in transparency and weather resistance and has a beautiful appearance. From such points, methacrylic resin molded products are, for example, signboard parts, display parts, lighting parts, interior parts, building parts, transportation equipment parts, electronic equipment parts, medical parts, optical parts, traffic relations. Used for parts. However, since the methacrylic resin has low flexibility, it is restricted from being used more widely.

  Patent Document 1 and Patent Document 2 include a method of blending methacrylic resin with multilayer structure acrylic rubber particles produced by emulsion polymerization as a method for improving the flexibility of methacrylic resin. By this method, a material having the same hardness as soft vinyl chloride can be obtained without containing a plasticizer. This method is currently practiced industrially. This multilayer structure acrylic rubber particle is composed of two or more layers, and a hard layer mainly composed of methyl methacrylate and a soft layer mainly composed of an acrylate ester such as n-butyl acrylate are substantially And have a spherical structure that overlaps alternately.

  However, in this method, when the multilayer structure acrylic rubber particles are blended with the methacrylic resin, the multilayer structure acrylic rubber particles may aggregate to form a lump (gel colony). In other words, the appearance of the molded product is impaired, particularly when used in optical member applications, and the commercial value may be significantly impaired. In addition, due to the influence of the emulsifier used in the emulsion polymerization method, the molded article has high water absorption, and easily absorbs whitening when the temperature rises after rain when immersed in warm water or outdoors. In particular, when used in a film, the decrease in transparency is significant.

  Patent Document 3 discloses a method of polymerizing a monomer having methyl methacrylate as a main component in the presence of a rubber-like substance composed of a butadiene-butyl acrylate copolymer. However, in this method, the appearance defect of the molded product caused by the poor dispersion of the rubber-like substance still remains.

  Patent Document 4 discloses a method of polymerizing a monomer mainly composed of methyl methacrylate in the presence of a partially hydrogenated conjugated diene polymer. However, since the partially hydrogenated conjugated diene polymer used in the method does not dissolve in methyl methacrylate, it must be dissolved in another solvent, and the manufacturing process becomes complicated. Furthermore, in this method, particle formation by phase inversion, particularly control of the particle size may be difficult.

  In Patent Document 5, polymethyl methacrylate or a copolymer based on methyl methacrylate 50 to 99% by mass, ethylene-vinyl acetate copolymer 0 to 50% by mass, and polymethyl methacrylate or methyl methacrylate And / or a graft copolymer comprising polyvinyl acetate and / or ethylene-vinyl acetate copolymer, and / or a copolymer based on polymethyl methacrylate or methyl methacrylate A methacrylic polymer composition comprising 0.5 to 50% by mass of a block copolymer composed of polyvinyl acetate or ethylene-vinyl acetate copolymer and template-polymerized is disclosed. However, the methacrylic polymer composition of Patent Document 5 has low transparency.

Japanese Patent Laid-Open No. 06-248035 JP 2002-277601 A Japanese Examined Patent Publication No. 45-26111 WO96 / 032440 Japanese Patent Laid-Open No. 06-345933

  An object of the present invention is to provide a methacrylic polymer composition capable of obtaining a molded article excellent in flexibility, hot water whitening resistance, transparency, and appearance (low roughness).

  The present inventors have made various studies in order to achieve the above object. As a result, the block copolymer (B) having a polymer block composed of repeating units derived from (meth) acrylic acid alkyl ester and a polymer block composed of repeating units derived from a conjugated diene compound (B) more than 80 parts by mass and more than 300 parts by mass It was found that a methacrylic polymer composition with significantly improved flexibility, appearance (brightness) and hot water whitening performance can be obtained by dispersing the following components in 100 parts by mass of the methacrylic resin (A). The present invention has been further studied and completed based on this finding.

That is, the present invention provides a polymer block comprising a repeating unit derived from a (meth) acrylic acid alkyl ester in a continuous phase comprising a methacrylic resin (A) having 50% by mass or more of a repeating unit derived from methyl methacrylate ( A block copolymer (B) having a polymer block (b) composed of a repeating unit derived from a conjugated diene compound is contained as a dispersed phase, and is blocked against 100 parts by mass of the methacrylic resin (A). It is a methacrylic polymer composition whose copolymer (B) is more than 80 parts by mass and not more than 300 parts by mass.
Moreover, this invention is a molded article which consists of the said methacrylic polymer composition.

  The methacrylic polymer composition of the present invention is excellent in molding processability, and the resulting molded article has good transparency. By molding the methacrylic polymer composition of the present invention, a molded product excellent in flexibility, hot water whitening resistance, and appearance (low roughness) can be obtained.

Hereinafter, the present invention will be described in more detail.
The methacrylic polymer composition of the present invention has a continuous phase composed of a methacrylic resin (A) having a repeating unit derived from methyl methacrylate of 50% by mass or more, and a repeating unit derived from a (meth) acrylic acid alkyl ester. A block copolymer (B) having a polymer block (a) and a polymer block (b) composed of repeating units derived from a conjugated diene compound is contained as a dispersed phase.

(Methacrylic resin (A))
The methacrylic resin (A) constituting the continuous phase in the present invention is a resin having 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more of repeating units derived from methyl methacrylate.
As repeating units derived from vinyl monomers other than repeating units derived from methyl methacrylate, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate; ethyl methacrylate, butyl methacrylate, etc. Methacrylic acid alkyl esters excluding methyl methacrylate; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, etc .; repeating derived from a non-crosslinkable monomer having only one alkenyl group in one molecule Units are listed.
The mass ratio of methyl methacrylate / other vinyl monomer is 50/50 to 100/0, preferably 80/20 to 99/1, more preferably 90/10 to 98/2.

The weight average molecular weight of the methacrylic resin (A) measured by GPC (gel permeation chromatography) is preferably 50,000 to 200,000, more preferably 60,000 to 150,000, and particularly preferably 70,000 to 120,000. . When the weight average molecular weight is less than 50,000, the tensile strength and elongation of the methacrylic polymer composition tend to decrease. When the weight average molecular weight exceeds 200,000, the fluidity of the methacrylic polymer composition is lowered and the moldability tends to be lowered.
Furthermore, the molecular weight distribution (= weight average molecular weight / number average molecular weight) measured by GPC of the methacrylic resin (A) is preferably 3.0 or less, more preferably 2.5 or less, and particularly preferably 2.3 or less. It is. When the molecular weight distribution exceeds 3.0, the tensile strength and elongation of the methacrylic polymer composition tend to decrease. The molecular weight and molecular weight distribution of the methacrylic resin can be controlled by adjusting the types and amounts of the polymerization initiator and the chain transfer agent.

[Block copolymer (B)]
The block copolymer (B) contained in the dispersed phase in the present invention comprises a polymer block (a) consisting of repeating units derived from (meth) acrylic acid alkyl ester and a repeating unit consisting of repeating units derived from a conjugated diene compound. And a combined block (b). The block copolymer (B) is preferably an elastomer.

The repeating unit derived from the (meth) acrylic acid alkyl ester constituting the polymer block (a) is obtained by addition polymerization of (meth) acrylic acid alkyl ester. “(Meth) acryl” means methacryl or acrylic.
Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate and the like, and examples of the acrylic acid alkyl ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, and acrylic acid. i-butyl, 2-ethylhexyl acrylate, and the like. These may be polymerized individually by 1 type, and may be copolymerized combining 2 or more types. Among these, a monomer or a combination of monomers giving a polymer block (a) having a glass transition temperature (Tg) of 23 ° C. or lower is preferable, and a monomer giving a polymer block (a) having a Tg of 0 ° C. or lower is preferable. A monomer or a combination of monomers is more preferable, and a monomer or a combination of monomers giving a polymer block (a) having a Tg of −10 ° C. or lower is still more preferable. As such a monomer, n-butyl acrylate and / or 2-ethylhexyl acrylate are preferable, and n-butyl acrylate is more preferable.

The repeating unit derived from the conjugated diene compound constituting the polymer block (b) is obtained by addition polymerization of the conjugated diene compound.
Examples of the conjugated diene compound include 1,3-butadiene, isoprene, pentadiene, 2,3-dimethylbutadiene and the like. These may be polymerized individually by 1 type, and may be copolymerized combining 2 or more types. Among these, a monomer or a combination of monomers giving a polymer block (b) having a glass transition temperature (Tg) of 0 ° C. or lower is preferable, and a polymer block (b) having a Tg of −10 ° C. or lower is given. A monomer or a combination of monomers is more preferred. Moreover, 1,3-butadiene and / or isoprene are preferable from the viewpoint of versatility, economy, and handleability, and 1,3-butadiene is more preferable.

  Conjugated diene compounds include those that undergo 1,4-addition polymerization and those that undergo 1,2- or 3,4-addition polymerization. When the conjugated diene compound undergoes 1,4-addition polymerization, it has a carbon-carbon double bond in the molecular main chain. When the conjugated diene compound is subjected to 1,2- or 3,4-addition polymerization, the conjugated diene compound has a vinyl group (side chain vinyl bond) bonded to the molecular main chain. The carbon-carbon double bond and / or the vinyl group bonded to the molecular main chain in the molecular main chain is a starting point for the graft reaction or the crosslinking reaction. The proportion of 1,2- or 3,4-addition polymerization of the conjugated diene compound can be increased by adding a polar compound such as ethers to the reaction system.

  The amount of side chain vinyl bonds in the polymer block (b) takes into consideration the graft reactivity with the methacrylic resin (A) as the continuous phase, the crosslinking reactivity of the dispersed phase, and the flexibility of the methacrylic polymer composition. To be selected.

  The amount of side chain vinyl bonds in the polymer block (b) is usually 10 mol% to 60 mol%, preferably 10 mol% to 50 mol%, more preferably 10 mol% to 35 mol%. If the amount of the side chain vinyl bond is too small, the graft bond with the methacrylic resin (A) that becomes the continuous phase is insufficient, and the flexibility tends to decrease. On the other hand, when the amount of the side chain vinyl bond is too large, the flexibility of the methacrylic polymer composition tends to decrease because the diameter of the dispersed phase becomes too small. The amount of the side chain vinyl bond is represented by the ratio [mol%] of 1,2-addition polymerization or 3,4-addition polymerization conjugated diene compound in 1 mol of the conjugated diene compound.

  The polymer block (b) may be obtained by partially hydrogenating a carbon-carbon double bond in the aforementioned molecular main chain and / or a vinyl group bonded to the molecular main chain. From the viewpoint of maintaining the effects of the present invention, the hydrogenation rate of the polymer block (b) is preferably less than 70 mol%, and more preferably less than 50 mol%. The method of hydrogenation is not particularly limited, and can be achieved by, for example, the method disclosed in Japanese Patent Publication No. 5-20442.

  The mass ratio of the polymer block (a) and the polymer block (b) is not particularly limited, but when the total of the polymer block (a) and the polymer block (b) is 100% by mass, The combined block (a) is preferably 45 to 75% by mass, more preferably 50 to 70% by mass. A polymer block (b) becomes like this. Preferably it is 25-55 mass%, More preferably, it is 30-50 mass%.

The block copolymer used in the present invention may have one each of the polymer block (a) and the polymer block (b), or the polymer block (a) and / or the polymer block. It may have two or more (b).
Examples of the bonding mode of the block copolymer include an ab type diblock copolymer, an aba type triblock copolymer, a bb type triblock copolymer, and an aba type. -B-type tetrablock copolymers and linear multi-block copolymers typified by ba-ba-type tetrablock copolymers, (ba-) _n , (ab-) _n, etc. And a star copolymer (radial star) block copolymer, a graft copolymer represented by agb, and the like. Note that g is a bond symbol indicating a graft bond, and n is a value greater than 2. The block copolymer (B) may have an inclined connecting part between the polymer block (a) and the polymer block (b). The inclined connecting portion is a portion having a repeating unit composition that gradually changes from the composition of the repeating unit of the polymer block (a) to the composition of the repeating unit of the polymer block (b). These block copolymers may be used individually by 1 type, and may be used in combination of 2 or more type.

  The block copolymer (B) is a diblock composed of a polymer block composed of repeating units derived from n-butyl acrylate monomers and a polymer block composed of repeating units derived from 1,3-butadiene monomers. From block copolymers, radial star copolymers, polymer blocks consisting of repeating units derived from 2-ethylhexyl acrylate monomers and polymer blocks consisting of repeating units derived from 1,3-butadiene monomers A diblock copolymer, a radial star copolymer, a polymer block composed of repeating units derived from methyl methacrylate monomer, and a polymer block composed of repeating units derived from n-butyl acrylate monomer Triblock copolymer comprising a polymer block composed of repeating units derived from 1,3-butadiene monomer Radial star copolymer.

As the block copolymer (B) used in the present invention, a star-shaped block copolymer is particularly preferable from the viewpoint of the mechanical strength of the dispersed phase.
The star block copolymer includes a copolymer in which a plurality of arm polymer blocks are linked by a group (coupling agent residue) derived from a polyfunctional monomer, a polyfunctional coupling agent, or the like.

  The arm polymer block constituting the star block copolymer is not limited by the bonding mode as long as it has the polymer block (a) and / or the polymer block (b). As the arm polymer block, an ab type diblock copolymer, an aba type triblock copolymer, a bb type triblock copolymer, an abaa- Examples thereof include a b-type tetrablock copolymer, a multiblock copolymer in which four or more polymer blocks (a) and polymer blocks (b) are bonded. The plurality of arm polymer blocks constituting the star block copolymer may be the same type of block copolymer or may be different types of block copolymers.

In the present invention, the chemical structural formula:
(Polymer block (b) -polymer block (a)-) _n X
A star block copolymer represented by the formula (wherein X represents a coupling agent residue and n represents a number exceeding 2) is particularly preferred.

The star block copolymer used in the present invention has a polystyrene-equivalent number average molecular weight calculated by GPC.
[Number average molecular weight of star block copolymer]> 2 × [Number average molecular weight of arm polymer block]
It is preferable to satisfy.
The ratio of [number average molecular weight of star block copolymer] / [number average molecular weight of arm polymer block] is sometimes referred to as the number of arms.

By setting the number average molecular weight of the star block copolymer to a range exceeding twice the number average molecular weight of the arm polymer block, the dispersed phase comprising the star block copolymer dispersed in the continuous phase The mechanical strength against shearing is increased, and a desired flexibility performance can be obtained. Since the number average molecular weight of the star block copolymer is more than 100 times the number average molecular weight of the arm polymer block is difficult to synthesize, the number average molecular weight of the industrially preferable star block copolymer is: The number average molecular weight of the arm polymer block is more than 2 times and 100 times or less, more preferably 2.5 to 50 times, and further preferably 3 to 10 times.
The star block copolymer used in the present invention is mainly composed of the arm polymer block linked by the coupling agent residue, but the arm not linked by the coupling agent residue. A polymer block may be included.

  A block copolymer is not specifically limited by the manufacturing method, It can employ | adopt from what was obtained by the method according to a well-known method. In general, as a method for obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerizing monomers as constituent units is employed. Living polymerization methods include, for example, a method of polymerizing using an organic rare earth metal complex as a polymerization initiator, an organic alkali metal compound as a polymerization initiator, and in the presence of an alkali metal or alkaline earth metal mineral salt. And an anion polymerization method using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound, an atom transfer radical polymerization (ATRP) method, and the like.

  Among the above production methods, the method of anionic polymerization using an organoalkali metal compound as a polymerization initiator in the presence of an organoaluminum compound is a narrower molecular weight distribution and a residual monomer under relatively mild temperature conditions. Is preferable in that it can produce a block copolymer with a small amount and has a low environmental load (mainly power consumption of a refrigerator necessary for controlling the polymerization temperature) in industrial production.

As the organic alkali metal compound used for the anionic polymerization, an organic lithium compound is preferable. ,
Specific examples of the organic lithium compound include methyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, isobutyl lithium, tert-butyl lithium, n-pentyl lithium, and n-hexyl lithium. Alkyllithium and alkyldilithium such as tetramethylenedilithium, pentamethylenedilithium and hexamethylenedilithium; aryllithium and aryldilithium such as phenyllithium, m-tolyllithium, p-tolyllithium, xylyllithium and lithium naphthalene Lithium; benzyl lithium, diphenylmethyl lithium, trityl lithium, 1,1-diphenyl-3-methylpentyl lithium, α-methylstyryl lithium, diisopropenyl benzene Aralkyllithium and aralkyldilithium such as dilithium produced by the reaction of butyllithium with lithium; lithium amides such as lithium dimethylamide, lithium diethylamide and lithium diisopropylamide; methoxylithium, ethoxylithium, n-propoxylithium, isopropoxylithium, n -Butoxylithium, sec-butoxylithium, tert-butoxylithium, pentyloxylithium, hexyloxylithium, heptyloxylithium, octyloxylithium, phenoxylithium, 4-methylphenoxylithium, benzyloxylithium, 4-methylbenzyloxylithium, etc. Lithium alkoxide of the following. These may be used alone or in combination of two or more.

Examples of the organoaluminum compound used in the above anionic polymerization include the following general formula:
AlR ¹ R ² R ³
(In the formula, R ¹ , R ² and R ³ may each independently have an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a substituent. A good aryl group, an aralkyl group which may have a substituent, an alkoxyl group which may have a substituent, an aryloxy group which may have a substituent or an N, N-disubstituted amino group; Or R ¹ represents any of the groups described above, and R ² and R ³ together represent an aryleneoxy group which may have a substituent.) Is mentioned.
Among the organoaluminum compounds, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isobutylbis (2,6-di-tert-butylphenoxy) aluminum, isobutyl [2,2′- Methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum is particularly easy in handling and allows the anionic polymerization reaction to proceed without deactivation under relatively mild temperature conditions. preferable. These may be used alone or in combination of two or more.

  In the above anionic polymerization, if necessary, an ether such as dimethyl ether, dimethoxyethane, diethoxyethane, 12-crown-4; triethylamine, N, N, N ′, N′-tetramethyl is included in the reaction system. Nitrogen-containing compounds such as ethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, pyridine, 2,2′-dipyridyl Can further coexist for stabilization of the polymerization reaction.

The star block copolymer can be obtained by adding a polyfunctional monomer to the block copolymer reaction solution obtained by the above-mentioned anionic polymerization or the like and copolymerizing it, or by adding the block copolymer reaction solution to the reaction solution of the block copolymer. It can be obtained by adding a polyfunctional coupling agent to cause a coupling reaction.
The polyfunctional monomer is a compound having two or more ethylenically unsaturated groups, and specifically includes allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, divinylbenzene, 1 , 6-hexanediol diacrylate and the like.
The polyfunctional coupling agent is a compound having 3 or more reactive groups, specifically, trichloromethylsilane, tetrachlorosilane, butyltrichlorosilane, bis (trichlorosilyl) ethane, tetrachlorotin, butyltrichlorotin, Examples include tetrachlorogermanium.

  The block copolymer (B) is not particularly limited by its refractive index, but when the methacrylic polymer composition of the present invention requires transparency, the refractive index of the block copolymer (B) is methacrylic. It is preferable to match the refractive index of the resin (A). Specifically, the refractive index of the block copolymer (B) is preferably 1.48 to 1.50, more preferably 1.485 to 1.495.

  The refractive index of the block copolymer (B) can be adjusted by selecting the kind of repeating unit constituting the polymer, the composition ratio, the amount of side chain vinyl bonds in the polymer block (b), and the like. For example, a diblock copolymer comprising a polymer block (a) composed of repeating units derived from n-butyl acrylate and an unhydrogenated polymer block (b) composed of repeating units derived from 1,3-butadiene. Then, when the content of n-butyl acrylate is 40 to 60% by mass and the content of 1,3-butadiene is 60 to 40% by mass with respect to the total mass of the diblock copolymer, the refractive index of polymethyl methacrylate And a transparent methacrylic polymer composition can be obtained.

  The total number average molecular weight (Mn) of the block copolymer (B) used in the present invention is 5,000 to 1,000,000 from the viewpoint of improving the flexibility of the resulting methacrylic polymer composition. It is preferably 10,000 to 800,000, more preferably 50,000 to 500,000.

  The amount of the block copolymer (B) is more than 80 parts by weight and 300 parts by weight or less, preferably 85 parts by weight or more and 250 parts by weight or less, more preferably 90 parts by weight with respect to 100 parts by weight of the methacrylic resin (A). The amount is 200 parts by mass or less. If the amount of the block copolymer (B) is too small, the flexibility of the methacrylic polymer composition tends to be lowered. When there is too much quantity of a block copolymer (B), it will become difficult to form the dispersed phase containing a block copolymer (B), and an external appearance will tend to deteriorate by generation | occurrence | production of a fuzz.

In the methacrylic polymer composition of the present invention, the dispersed phase comprising the block copolymer (B) is dispersed in the continuous phase comprising the methacrylic resin (A). In the methacrylic polymer composition of the present invention, since the ratio of the dispersed phase to the continuous phase is relatively large, the dispersed phases may be in contact with each other.
The average diameter of the dispersed phase is usually 0.05 to 2 μm, preferably 0.05 to 1 μm, more preferably 0.08 to 0.5 μm. If the average diameter of the dispersed phase is small, the flexibility tends to decrease, and if the average diameter of the dispersed phase is large, the transparency and surface smoothness tend to decrease.

  The dispersed phase contains a sea-island structure of the block copolymer (B) and the methacrylic resin (A). The sea-island structure of the dispersed phase is obtained by cutting a molded product of a methacrylic polymer composition with a diamond knife to obtain an ultrathin section, staining the section with osmium tetroxide, and observing it with a transmission electron microscope. Can be confirmed.

In dyeing with osmium tetroxide, the polymer block (b) in the block copolymer (B) is dyed. The dispersed phase of the sea-island structure is composed of a sea phase composed of a dyed portion (block copolymer (B)) and an island phase composed of an undyed portion (methacrylic resin (A)).
The average diameter of the island phase is usually 0.01 to 0.2 μm, preferably 0.05 to 0.1 μm.
The area ratio of the island phase / sea phase observed in the molded plate section is preferably 20/80 or more, more preferably 30/70 to 70/30.
Moreover, it is preferable that the ratio of the dispersed phase which comprised the sea-island structure is 20 mass% or more of all the dispersed phases, and it is more preferable that it is 30-100 mass%.

The methacrylic polymer composition of the present invention is not particularly limited by the production method. For example, it can be obtained by adding the block copolymer (B) constituting the dispersed phase to the methacrylic resin (A) constituting the continuous phase and melt-kneading in a uniaxial or biaxial melt extruder or the like. it can. However, in this invention, the methacrylic polymer composition obtained by the manufacturing method (in situ method) described below is preferable.
The in situ method is a method in which a material that becomes a continuous phase or a dispersed phase is generated in the presence of a material that becomes a dispersed phase or a continuous phase, and a composition composed of the continuous phase and the dispersed phase is directly formed. In the present invention, an in situ method is preferred in which a methacrylic resin (A) that becomes a continuous phase is produced in the presence of the block copolymer (B) that becomes a dispersed phase. Then, the manufacturing method of the methacrylic polymer composition by an in situ method is demonstrated.

In the in situ method, first, a monomer mixture (A _m ), (meth) acrylic consisting of 50 to 100% by mass of methyl methacrylate and 0 to 50% by mass of another vinyl monomer copolymerizable with methyl methacrylate. A block copolymer (B) having a polymer block (a) comprising a repeating unit derived from an acid alkyl ester and a polymer block (b) comprising a repeating unit derived from a conjugated diene compound, and optionally a solvent A raw material liquid containing (C) is prepared.

The methyl methacrylate and other vinyl monomers copolymerizable with methyl methacrylate used in the monomer mixture (A _m ) are the same as those described above.

The amount of the block copolymer (B) in the raw material liquid is more than 80 parts by weight and less than 300 parts by weight, preferably 85 parts by weight to 250 parts by weight, with respect to 100 parts by weight of the monomer mixture (A _m ). More preferably, it is 90 to 220 mass parts. When the amount of the block copolymer (B) is less than 80 parts by mass, the effect of improving the flexibility of the methacrylic polymer composition is small. When the amount of the block copolymer (B) is more than 300 parts by mass, it becomes difficult to form a dispersed phase containing the block copolymer (B).

The solvent (C) used in the present invention includes a monomer mixture (A _m ), a polymer of the monomer mixture (A _m ) (that is, a methacrylic resin (A)), and a block copolymer (B). As long as it has the ability to dissolve in water, it is not particularly limited. For example, aromatic hydrocarbons such as benzene, toluene, and ethylbenzene are desirable. Moreover, you may mix and use 2 or more types of solvents as needed. In the case of using a mixed solvent, the monomer mixture (A _m ), the monomer mixture (A _m ) polymer and the block copolymer (B) can be dissolved in the monomer mixture (A). A _m ), a monomer mixture (A _m ) polymer, and a solvent that cannot dissolve the block copolymer (B) may be contained in the mixed solvent. For example, the mixed solvent may contain alcohols such as methanol, ethanol and butanol; ketones such as acetone and methyl ethyl ketone; hydrocarbons such as hexane; alicyclic hydrocarbons such as cyclohexane and the like.

Solubility parameter of the solvent used for the polymerization (SP value), from 18.5 to 21.0 (MPa) ^1/2, more preferably 19.0~20.5 (MPa) ^1/2, 19.5~ 20.0 (MPa) ^1/2 is more preferable. In this case, one type of solvent may be used, or two or more types may be mixed. When mixing 2 or more types, it calculates by an addition rule according to a composition ratio, and calculates | requires SP value. When the SP value is less than 18.5 (MPa) ^1/2 , the solubility of the methacrylic resin (A) is remarkably lowered, and when it exceeds 21.0 (MPa) ^1/2 , the dissolution of the block copolymer (B) is achieved. This is not preferable because the properties are significantly reduced.

The amount of the solvent (C) in the raw material liquid is preferably 0 to 300 parts by mass, more preferably 50 to 100 parts by mass with respect to a total of 100 parts by mass of the monomer mixture (A _m ) and the block copolymer (B). 250 parts by mass, particularly preferably 100 to 200 parts by mass. In the methacrylic polymer composition of the present invention, since the ratio of the continuous phase to the dispersed phase is relatively small, the solvent (C) is used to increase the volume of the continuous phase after phase inversion in the in situ method. It is preferable.

The raw material liquid can be prepared by uniformly dissolving the block copolymer (B) in the monomer mixture (A _m ). Dissolution is accelerated by stirring and is further accelerated by heating to about 30-60 ° C. Moreover, when adjusting a raw material liquid, the said solvent (C) can be used as needed.

Next, the raw material liquid is polymerized. Simultaneously with the polymerization of the raw material liquid, the polymerization reaction of the monomer mixture (A _m ) proceeds, and at the same time, the graft reaction and / or crosslinking between the block copolymer (B) and the monomer mixture (A _m ). The reaction proceeds.
For polymerization of the raw material liquid, a radical polymerization initiator is usually used. Moreover, a chain transfer agent is used as needed.

  The polymerization initiator is not particularly limited as long as it generates a reactive radical. As polymerization initiators, azo compounds such as azobisisobutyronitrile and azobiscyclohexylcarbonitrile; benzoyl peroxide, t-butylperoxy 2-ethylhexanoate, t-butylperoxybenzoate, di-t- Butyl peroxide, dicumyl peroxide, 1,1-di (t-butylperoxy) 3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, 1,1-di (t-butylperoxy) Examples thereof include organic peroxides such as cyclohexane and t-hexylperoxyisopropyl monocarbonate. These polymerization initiators may be used alone or in combination of two or more. Further, the addition timing and the addition method of the polymerization initiator are not particularly limited as long as the predetermined polymerization reaction proceeds, but the pre-stage polymerization is performed with the polymerization initiator charged at the start of the polymerization, and during the reaction It is preferable to add a polymerization initiator and perform post-stage polymerization.

  As the chain transfer agent, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, ethylene glycol bisthiopropionate, butanediol bisthioglycolate, Alkyl mercaptans such as butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris- (β-thiopropionate), pentaerythritol tetrakisthiopropionate; α-methylstyrene dimer; terpinolene and the like can be mentioned. These can be used alone or in combination of two or more.

The polymerization of the raw material liquid is preferably performed by a bulk polymerization method or a solution polymerization method from the initial stage of polymerization until phase inversion occurs. When polymerization is performed by a bulk polymerization method or a solution polymerization method, at the initial stage of polymerization, polymerization of the monomer mixture (A _m ) proceeds mainly to produce a methacrylic resin. As the polymerization conversion increases, the proportion of the solution phase of the methacrylic resin produced by the polymerization of the monomer mixture (A _m ) increases, and the solution phase of the methacrylic resin and the solution phase of the block copolymer (B) Phase separates. When the polymerization conversion rate further increases, an action for stabilizing the whole phase works, and the solution phase of the methacrylic resin and the solution phase of the block copolymer (B) are reversed by the shearing force by stirring. The solution phase of the system resin becomes a continuous phase, and the solution phase of the block copolymer (B) becomes a dispersed phase. At this time, the viscosity decreases. The polymerization conversion rate of the monomer mixture (A _m ) when this phase inversion occurs is the volume ratio of the solution phase of the methacrylic resin to the solution phase of the block copolymer (B), the block copolymer (B) The molecular weight, the graft ratio to the block copolymer (B) before phase inversion, and when a solvent is used, it varies depending on the amount of solvent and the type of solvent.

  In the polymerization of the raw material liquid, it is preferable to apply a shearing force to the raw material liquid from the initial stage of polymerization until phase inversion occurs. Accordingly, preferred examples of the apparatus for polymerizing the raw material liquid include a tank reactor equipped with a stirrer, a cylindrical reactor equipped with a stirrer, and a cylindrical reactor having static stirring ability. One or more of these apparatuses may be used, or a combination of two or more different reactors may be used. Further, the polymerization may be either a batch type or a continuous type.

The diameter of the dispersed phase depends on factors such as the number of stirring revolutions in the case of a reactor equipped with a stirrer; the linear velocity of the reaction liquid, the viscosity of the polymerization system, and the phase inversion in the case of a static stirring reactor represented by a tower reactor It can be controlled by various factors such as the graft ratio to the previous block copolymer (B).
After phase inversion occurs, bulk polymerization method or solution polymerization method can be applied, but suspension polymerization method and cast polymerization method can also be applied besides these.

In the present invention, the polymerization conversion rate of the monomer mixture (A _m ) is preferably 70% by mass or more, more preferably 80% by mass or more. If the polymerization conversion rate is lower than this, the crosslinking reaction and graft reaction in the dispersed phase containing the block copolymer (B) formed by phase inversion hardly proceed sufficiently. When the crosslinking reaction and graft reaction are not sufficiently advanced, the dispersed phase in the methacrylic polymer composition is easily broken by mechanical shearing such as an extruder or a kneading machine, and the flexibility is sufficient. At the same time, the mechanical strength may change depending on the molding method. In order to further promote the crosslinking reaction and the graft reaction and increase the flexibility, it is preferable to add a polymerization initiator during the reaction.

  The presence or absence of a dispersed phase comprising the block copolymer (B) in the middle of polymerization and the diameter of the dispersed phase were determined by extracting a part of the raw material liquid during polymerization and subjecting it to suspension polymerization. The method of observing the morphology of the polymer composition with a scanning electron microscope, or removing a part of the raw material liquid in the middle of polymerization, drying and devolatilizing it, removing the unreacted monomer and solvent, The morphology of the composition can be confirmed by a method of observing with a scanning electron microscope.

After the polymerization conversion rate of the monomer mixture (A _m ) reaches 70% by mass or more, devolatilization is performed to remove the unreacted monomer and the solvent. Examples of the devolatilization method include an equilibrium flash method and an adiabatic flash method. In particular, in the adiabatic flash method, devolatilization is preferably performed at a temperature of 200 to 300 ° C, more preferably 220 to 270 ° C. If it is less than 200 ° C., it takes time for devolatilization, and when devolatilization is insufficient, the molded product may have poor appearance such as silver. On the other hand, if the temperature exceeds 300 ° C., the methacrylic polymer composition may be colored due to oxidation, burning, or the like. Examples of the apparatus used for devolatilization include a flash drum, a biaxial devolatilizer, a thin film evaporator, and an extruder. The residual volatile content is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, and still more preferably 0.3% by mass or less. When the residual volatile content exceeds 0.5% by mass, the heat distortion temperature tends to decrease.

  In the methacrylic polymer composition of the present invention, a known antioxidant, ultraviolet absorber, light stabilizer, lubricant, mold release agent, antistatic agent, polymer processing aid, flame retardant, Dyes and pigments, light diffusing agents, flexibility modifiers, phosphors, and the like can be added. Moreover, the methacrylic polymer composition of the present invention can be used after diluted with a normal methacrylic resin (D). In addition, other resins such as AS resin, ABS resin, AES resin, AAS resin, MS resin, MBS resin, styrene resin, high-impact polystyrene resin, and vinyl chloride resin can be used.

Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic anilides, malonic esters, formamidines, and the like. These can be used alone or in combination of two or more. Among these, from the viewpoint of suppressing the yellowness of the molded product, an ultraviolet absorber having a maximum molar extinction coefficient ε _{max at} a wavelength of 380 to 450 nm of 1200 dm ³ · mol ⁻¹ cm ⁻¹ or less is preferable, and 600 dm ³ · mol ^-1 cm ^-1 UV absorber is more preferably not more than, 300Dm ultraviolet absorber is ³ · mol ^-1 cm ^-1 or less is particularly preferred.

In addition, the measurement of the maximum value ε _max of the molar extinction coefficient of the ultraviolet absorber is performed by sufficiently dissolving 10.00 mg of the ultraviolet absorber (molecular weight (Mw)) in 1 L of cyclohexane so that there is no undissolved substance by visual observation. This solution was poured into a 1 cm × 1 cm × 3 cm quartz glass cell, and the absorbance at a wavelength of 380 to 450 nm was measured using a U-3410 type spectrophotometer manufactured by Hitachi, Ltd. From the maximum value (A _max ), molar absorption was measured. The maximum coefficient ε _max was calculated by the following equation.
ε _max = [A _max / (10 × 10 ⁻³ )] × Mw
As an ultraviolet absorber having a maximum molar extinction coefficient ε _{max at a} wavelength of 380 to 450 nm of 1200 dm ³ · mol ⁻¹ cm ⁻¹ or less, 2-ethyl-2′-ethoxy-oxalanilide (Clariant Japan, Inc .; product) Name Sundeyuboa VSU).

  The amount of the ultraviolet absorber is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and still more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the methacrylic polymer composition. Part. When the amount of the ultraviolet absorber is less than 0.001 part by mass, the effect of suppressing the resin deterioration due to ultraviolet rays tends not to be exhibited sufficiently. If the amount exceeds 5 parts by mass, the mold is likely to become dirty during molding, so that it is easy to cause a decrease in yield and productivity due to mold cleaning, etc., and to cause the occurrence of silver and to the eyes. When using a methacrylic polymer composition for a film, you may make a ultraviolet absorber contain 0.01-5 mass parts with respect to 100 mass parts of methacrylic polymer compositions.

In the present invention, a light stabilizer such as a hindered amine represented by a compound having a 2,2,6,6-tetraalkylpiperidine skeleton may be used in combination.
Examples of hindered amines include dimethyl succinate / 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly ((6- (1,1,3 , 3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl) ((2,2,6,6-tetramethyl-4-pipedyl) imino) hexamethylene ((2,2, 6,6-tetramethyl-4-pipedyl) imino)), 2- (2,3-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2, 6,6-pentamethyl-4-piperidyl), 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl) -4-piperidyl), N, N′-bis (3-a Nopropyl) ethylenediamine / 2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -6-chloro-1,3,5-triazine condensate, Examples thereof include bis (2,2,6,6-tetra-methyl-4-pipedyl) sebacate and bis (2,2,6,6-tetramethyl-4-piperidyl) succinate.
The amount of the light stabilizer is preferably 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the methacrylic polymer composition. When using a methacrylic polymer composition for a film, you may make a light stabilizer contain 0.001-0.5 mass part with respect to 100 mass parts of methacrylic polymer compositions.

  Examples of the antioxidant include phosphorus-based antioxidants, hindered phenol-based antioxidants, thioether-based antioxidants, and the like. These can be used alone or in combination of two or more. Among these, phosphorus antioxidants and hindered phenol antioxidants are preferably used from the viewpoint of preventing the deterioration of optical properties due to coloring.

  Examples of phosphorus antioxidants include 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphos. Phyto, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, bis [ 2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid and the like. Among these, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite and tris (2,4-di-t-butylphenyl) phosphite are preferable.

  Examples of the hindered phenol antioxidant include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octyl) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3 , 5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di- t-butyl-4-hydroxyphenylpropionate), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hex Methylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl -2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, octyl Diphenylamine, 2,4-bis [(octylthio) methyl] -o-cresol, isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and the like. Among these, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name “IRGANOX1010”, manufactured by Ciba Special Chemicals), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (trade name “IRGANOX1076”, manufactured by Ciba Special Chemicals) is preferable.

  The amount of the antioxidant is preferably 0.001 to 1 part by mass, more preferably 0.005 to 0.5 part by mass, and still more preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the methacrylic polymer composition. 0.3 parts by mass. If the amount of the antioxidant is less than 0.001 part by mass, the effect of preventing the heat coloring of the molded product at a high temperature tends not to be sufficiently exhibited. On the other hand, when the amount of the antioxidant exceeds 1 part by mass, it causes a decrease in yield due to mold contamination and a decrease in productivity due to mold cleaning, etc. There is a tendency that the molded product is burned and the hue is lowered, or foreign matters are generated in the molded product.

  Examples of the mold release agent include higher alcohol and / or glycerin monoester. Examples of higher alcohols include cetyl alcohol and stearyl alcohol. Examples of the glycerin monoester used in the present invention include glycerides of higher fatty acids such as stearic acid monoglyceride and stearic acid diglyceride. When the higher alcohol and glycerol monoester are used in combination, the ratio is not particularly limited, but the mass ratio of higher alcohol / glycerol monoester is preferably 2.5 / 1 to 3.5 / 1, more preferably 2.8. / 1 to 3.2 / 1.

  The amount of the release agent is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and more preferably 0.1 parts by mass with respect to 100 parts by mass of the methacrylic polymer composition. More preferably, it is at most parts. If the amount of the release agent exceeds 0.5 parts by mass, it tends to cause a decrease in yield due to mold contamination and a decrease in productivity due to mold cleaning. It becomes easy to produce the eyes and the eyes at the time of extrusion molding.

  The polymer processing aid has an effect on dimensional accuracy and thinning when molding a methacrylic polymer composition. The polymer processing aid can be usually produced as polymer particles having a particle size of 0.05 to 0.5 μm by an emulsion polymerization method. The polymer particles may be so-called single layer particles having a single composition and a single intrinsic viscosity, or may be multi-layer particles having two or more layers having different compositions or intrinsic viscosities. Among these, particles having a two-layer structure having a low intrinsic viscosity layer in the inner layer and a high intrinsic viscosity layer having an intrinsic viscosity of 5 dl / g or more in the outer layer are preferable. The intrinsic viscosity of the polymer processing aid is 3 to 6 dl / g, and if it is less than 3 dl / g, a sufficient improvement effect on moldability is not recognized. If it exceeds 6 dl / g, the melt fluidity tends to be lowered.

  When the polymer processing aid is used, the blending amount is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the methacrylic polymer composition. If the polymer processing aid is less than 0.05 parts by mass, a sufficient improvement effect in dimensional accuracy during molding is not recognized. On the other hand, if it exceeds 10 parts by mass, the melt fluidity tends to be lowered.

Examples of the organic dye include terphenyl having a function of converting ultraviolet rays that are considered harmful to the resin into visible light.
Examples of the light diffusing agent or matting agent include glass fine particles, polysiloxane-based crosslinked fine particles, crosslinked polymer fine particles, talc, calcium carbonate, and barium sulfate.
Examples of the phosphor include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent brighteners, and fluorescent bleaching agents.

  Moreover, a flexibility modifier can be used for the methacrylic polymer composition of the present invention. Examples of the flexibility modifier include a core-shell type modifier containing acrylic rubber or diene rubber as a core layer component, and a modifier containing a plurality of rubber particles.

  If the methacrylic polymer composition of the present invention is used, a molded article having excellent flexibility can be obtained. For example, a molded product can be obtained by conventionally known melt heating molding such as injection molding, compression molding, extrusion molding, vacuum molding and the like. In the molded product, the size and shape of the dispersed phase comprising the block copolymer (B) may vary to some extent, but no apparent change is observed. The molded article that has been heat-melt molded has at least the same characteristics as the corresponding methacrylic polymer composition.

  Since the methacrylic polymer composition of the present invention is excellent not only in flexibility but also in weather resistance and transparency, it is suitable for various molded articles or molded parts. Applications include, for example, billboard supplies such as advertising towers, stand signboards, sleeve signboards, billboard signs, and rooftop signs; display supplies such as showcases, dividers, and store displays; fluorescent lamp covers, mood lighting covers, lamp shades, light Lighting products such as ceilings, light walls, and chandeliers; interior products such as pendants and mirrors; doors, domes, partitions, staircases, balcony lumbars, and building parts for leisure buildings; bus shading plates; acoustic images Electronic equipment parts such as nameplates, stereo covers, TV protective masks, vending machines; medical equipment parts such as incubators and X-ray parts; equipment related to machine covers, instrument covers, experimental equipment, rulers, dials, observation windows, etc. Components: LCD protective plate, light guide plate, light guide film, Fresnel lens, lenticular lens, front plate of various displays, diffusion Optical parts such as traffic signs, traffic-related parts such as signboards, automotive interior surface materials, mobile phone surface materials, marking film film members, washing machine canopy materials and control panels, rice cooker top surfaces Other uses include household appliances such as panels; greenhouses, clock panels, sanitary, desk mats, game parts, toys, masks for face protection during welding, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In the synthesis of the block copolymer (B) used in Examples and Comparative Examples, chemicals dried and purified by a conventional method were used and the synthesis examples shown below were performed. At that time, measurement of the polymerization conversion rate and analysis of the synthesized block copolymer (B) were carried out by the following methods. Moreover, the analysis of a methacrylic polymer composition, the measurement of a mechanical characteristic, and an optical characteristic were performed with the following method.

(1) Measurement of number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) and block copolymer production rate by gel permeation chromatography (GPC) Apparatus: Gel Perm manufactured by Tosoh Corporation Eation chromatograph (HLC-8020)
Column: Tosoh TSKgel G2000H _HR (1) and GMH _HR- M (2) connected in series Eluent: Tetrahydrofuran Eluent flow rate: 1.0 ml / min Column temperature: 40 ° C
Detection method: differential refractive index (RI) meter Calibration curve: created using standard polystyrene

(2) Measurement of polymerization conversion rate of charged monomer by gas chromatography (GC) Apparatus: Gas chromatograph GC-14A manufactured by Shimadzu Corporation
Column: GL Sciences Inc. INERT CAP 1 (df = 0.4 μm, 0.25 mm ID × 60 m)
Analysis conditions: injection temperature 180 ° C., detector temperature 180 ° C., 60 ° C. (5 minutes hold) → temperature increase rate 10 ° C./min→200° C. (10 minutes hold)

(3) Analysis of molecular structure of block copolymer by nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum) The block copolymer was dissolved in deuterated chloroform to obtain a test solution, and ¹ H-NMR (Nuclear Magnetic, manufactured by JEOL Ltd.) The test solution was analyzed using a resonance apparatus (JNM-LA400), and a proton (= CH ₂ ) of 1,2-vinyl with a chemical shift of 4.7 to 5.2 ppm (hereinafter referred to as signal C ₀ ), The integral intensity of the vinyl proton (= CH-) at a chemical shift of 5.2 to 5.8 ppm (hereinafter referred to as signal D ₀ ) is obtained, and the side chain vinyl bond amount V ₀ [mol%] is calculated by the following equation. Asked.
V ₀ = _{[(C 0/2) / {} C 0/2 + (D 0 -C 0/2) / 2} ] × 100

(4) Glass transition temperature (Tg)
The glass transition temperature (Tg) of poly (n-butyl acrylate) used as the polymer block (a) is the value described in “POLYMER HANDBOOK FOURTH Edition, page VI / 199, Wiley Interscience, New York, 1998” (−49 ° C) was used.
The glass transition temperature (Tg) of poly1,3-butadiene used as the polymer block (b) is 1,2-vinyl bond amount described in “ANIONIC POLYMERIZATION, page 434, MARCEL DEKKER, Inc. 1996”. A value derived from the relationship between Tg and Tg was used.

(5) Refractive index (nd)
The block copolymer (B) was uniformly dissolved in toluene so as to be 30% by mass. The density and refractive index of the solution and toluene were measured at room temperature, and the refractive index of the block copolymer (B) was determined using the following formulas (Formula 1) to (Formula 3). Furthermore, polymethyl methacrylate having a known refractive index (nd = 1.492) was measured by the same method, and a refractive index measurement calibration coefficient was obtained by this method to calibrate the refractive index of the block copolymer (B). .
(Nd ² −1) / (nd ² +2) × V = r = constant (Expression 1)
r ₃ = w ₁ r ₁ + w ₂ r ₂ (Formula 2)
V ₂ = 1 / ρ ₁ −1 / w ₂ (1 / ρ ₁ −1 / ρ ₃ ) (Equation 3)
nd: refractive index, V: specific volume, r: molecular refraction, w: mass fraction ρ: density subscript 1: toluene subscript 2: block copolymer (B) subscript 3: solution Actual measurement: V ₃ , nd ₃ , V ₁ , nd ₁
Formula (1) and Formula (2) Source: Polymer Experimental Studies Vol. 12 Thermodynamic, Electrical and Optical Properties 1984 Kyoritsu Publishing Formula (3) Source: Polymer Experimental Studies Vol. 11 Polymer Solution Showa 57 years Kyoritsu Publishing

(6) Structure of disperse phase The molded product was cut out using a diamond knife to obtain an ultrathin slice, this slice was stained with osmium tetroxide, and the observation image was photographed using a transmission electron microscope. A dispersed phase comprising 30 block copolymers (B) was selected at random, the diameters of the dispersed phases were measured, and the average value thereof was expressed.
In addition, the polymer block (b) in the block copolymer (B) is dyed by the above dyeing, and the morphology of the methacrylic polymer composition can be observed. The methacrylic polymer composition of the present invention contains a continuous phase composed of an undyed methacrylic resin (A) and a dispersed phase comprising a dyed block copolymer (B). Includes a sea-island structure of a dyed portion (sea phase comprising a block copolymer (B)) and a non-dyed portion (island phase comprising a methacrylic resin (A)).

(7) Evaluation of flexibility of molded product Hardness was measured based on ISO 48 using an A-type hardness meter (manufactured by Oscar).

(8) Measurement of tensile properties of molded product In accordance with ISO 37, tensile strength and tensile elongation were measured.

(9) Evaluation of transparency of molded product Based on ISO 13468-1, the haze of a molded product having a thickness of 3 mm was measured.

(10) Warm water whitening resistance A 3 mm thick flat plate prepared by injection molding was immersed in warm water at 70 ° C. for 8 hours, then immersed in distilled water at room temperature, cooled to room temperature, then taken out and gauze on the surface. The light transmittance after wiping off the water and immersion in hot water (visible light: 600 nm) was measured, and the difference before and after immersion was determined.

(11) Evaluation of film forming property Pellets made of a methacrylic polymer composition were melt-extruded through a T-die extruder having a lip width of 300 mm and an upper and lower gap of 0.3 mm, and were drawn while being stretched in the vertical direction. A 2 mm film was produced. From the minimum thickness D _min (mm) and the maximum thickness D _max (mm) of the film measured from 10 minutes to 30 minutes after the start of extrusion, the thickness variation rate is obtained from the following formula, and the following evaluation criteria are used. Therefore, the film forming property was evaluated.
Film thickness variation rate (%) = {(D _max −D _min ) / D _min } × 100
[Evaluation criteria for film-forming properties]
A: The thickness variation rate is less than 5%, and the film-forming property is extremely good.
A: The thickness variation rate is 5 to 20%, and the film forming property is almost good.
X: The thickness variation rate exceeds 20%, and the film forming property is extremely poor.

(12) Laminate formability A laminate produced by co-melt extrusion molding is visually observed to check for whitening at the flow mark and the layer interface, and when neither the flow mark nor the whitening of the layer interface occurs. (○), the case where the flow mark and / or the whitening of the layer interface occurred was evaluated as defective (×).

(13) Film appearance evaluation The number per unit area of butts (fish eyes) of a 50 μm-thick film was measured with a gel counter (model FS-5 / manufactured by Optical Control Systems).
[Evaluation criteria for film appearance evaluation]
◎ The number per square meter area is less than 10,000. ○ The number per square meter area is 10,000 or more and less than 50,000. X: The number per square meter area is 50,000 or more.

(14) Low-temperature bendability of laminated product A polyurethane primer was applied to both sides of a 100 μm polypropylene film, and silk screen printing was applied to one side thereof. A film made of the methacrylic polymer composition of the present invention was laminated on the printing surface side of the printing film with an embossing roll to obtain a laminate. This laminate is bonded to a 0.5 mm-thick steel sheet using a polyurethane adhesive so that the film surface made of the methacrylic polymer composition becomes the surface layer, and the film made of the methacrylic polymer composition on the surface layer. A laminate having a layer was obtained. Using the laminate, a 90 ° C. bending test was performed in an atmosphere of 20 ° C. and −20 ° C. Specifically, the laminate was cut into a size of 10 cm × 10 cm, bent so that the radius of curvature was 3 mm, and held for 4 seconds. The low temperature bendability of the laminate was evaluated according to the following evaluation criteria.
[Evaluation criteria for low-temperature bendability of laminated products]
○: Good without film breaks and cracks ×: Cracks and breaks in film occurred

<< Synthesis Example 1 >> Production of Block Copolymer (B-1) (1) 801 ml of toluene and 0.0021 ml of 1,2-dimethoxyethane were put into a 1.5 liter autoclave vessel equipped with a stirrer and purged with nitrogen for 20 minutes Went. To this, 1.1 ml of a cyclohexane solution of sec-butyllithium having a concentration of 1.3 mol / l was added, and then 99 ml of 1,3-butadiene was added and reacted at 30 ° C. for 3 hours to contain a 1,3-butadiene polymer. A reaction mixture was obtained. As a result of sampling analysis of a part of the obtained reaction mixture, the 1,3-butadiene polymer in the reaction mixture has a number average molecular weight (Mn) of 82,000 and a molecular weight distribution (Mw / Mn) of 1.07. The side chain vinyl bond amount was 20 mol%, and the glass transition temperature of the 1,3-butadiene polymer (polymer block (b)) was −86 ° C.

(2) The reaction mixture obtained in (1) above is cooled to −30 ° C., and toluene containing 0.45 mol / l isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum 11.0 ml of the solution and 8.1 ml of 1,2-dimethoxyethane were added and stirred for 10 minutes to obtain a homogeneous solution.

(3) Next, while vigorously stirring the solution obtained in the above (2), 70 ml of n-butyl acrylate was added and polymerized at −30 ° C. for 3 hours. As a result of sampling a part of the obtained reaction mixture and analyzing the molecular weight by GPC (polystyrene conversion), the number average molecular weight of the butadiene-n-butyl diblock copolymer in the reaction mixture is 132,000. The weight average molecular weight / number average molecular weight ratio (Mw / Mn) was 1.03, and the refractive index was 1.492. The glass transition temperature of the polymer block (a) obtained by polymerization of n-butyl acrylate was −49 ° C.

(4) The block copolymer (B-1) was obtained by putting the reaction mixture obtained by said (3) in 8000 ml of methanol, and precipitating. The yield of the obtained block copolymer (B-1) was almost 100%. The block copolymer (B-1) is composed of 50% by mass of a polymer block (b) consisting of repeating units derived from 1,3-butadiene and a polymer block consisting of repeating units derived from n-butyl acrylate ( a) A diblock copolymer comprising 50% by mass. Table 1 shows the characteristics of the block copolymer (B-1). In Table 1, BA means n-butyl acrylate, and Bd means 1,3-butadiene.

<< Synthesis Example 2 >> Production of Block Copolymer (B-2) (1) To a 1.5 liter autoclave vessel equipped with a stirrer, 801 ml of toluene and 0.12 ml of tetrahydroxyfuran were charged and purged with nitrogen for 20 minutes. . Then, 3.8 ml of a cyclohexane solution of sec-butyllithium having a concentration of 1.3 mol / l was added, and then 101 ml of 1,3-butadiene was added and reacted at 30 ° C. for 3 hours to obtain a 1,3-butadiene polymer. A reaction mixture containing was obtained.
As a result of sampling analysis of a part of the obtained reaction mixture, the 1,3-butadiene polymer in the reaction mixture has a number average molecular weight (Mn) of 25,000 and a molecular weight distribution (Mw / Mn) of 1.06. The side chain vinyl bond amount was 20 mol%, and the glass transition temperature of the 1,3-butadiene polymer (polymer block (b)) was −86 ° C.

(2) The reaction mixture obtained in (1) above is cooled to −30 ° C., and toluene containing 0.45 mol / l isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum 36.7 ml of the solution and 8.1 ml of 1,2-dimethoxyethane were added and stirred for 10 minutes to obtain a homogeneous solution.

(3) Next, while vigorously stirring the solution obtained in the above (2), 68 ml of n-butyl acrylate was added and polymerized at −15 ° C. for 13 hours. A part of the obtained reaction mixture was sampled, and the molecular weight was analyzed by GPC (polystyrene conversion). As a result, the butadiene-n-butyl diblock copolymer (arm polymer block) in the reaction mixture had a number average molecular weight. The weight average molecular weight / number average molecular weight ratio (Mw / Mn) was found to be 1.02. The glass transition temperature of the polymer block (a) obtained by polymerization of n-butyl acrylate was −49 ° C.

(4) The reaction mixture obtained in the above (3) was kept at −15 ° C., and with vigorous stirring, 4.3 ml of 1,6-hexanediol diacrylate was added and polymerized for 2 hours. Then about 1 ml of methanol was added to stop the polymerization.

(5) A block copolymer (B-2) was obtained by putting the reaction mixture obtained in the above (4) into 8000 ml of methanol and precipitating it. The yield of the obtained block copolymer (B-2) was almost 100%.
The obtained block copolymer (B-2) was a mixture of a star block copolymer and an arm polymer block. The proportion of the star block copolymer calculated from the area ratio of GPC was 92% by mass.
The number average molecular weight (Mn) of the star block copolymer was 110,000 (number of arms = 2.75), and its Mw / Mn was 1.16.
The block copolymer (B-2) is a polymer block (b) 51% by mass derived from a repeating unit derived from 1,3-butadiene and a polymer block composed of a repeating unit derived from n-butyl acrylate. (A) A diblock copolymer consisting of 49% by mass was included as an arm polymer block.
The refractive index of the block copolymer (B-2) was 1.492. Table 1 shows the characteristics of the block copolymer (B-2).

<Example 1>
To an autoclave with a stirrer and a sampling tube, 21 parts by mass of methyl methacrylate, 1 part by mass of methyl acrylate, 30 parts by mass of toluene, 30 parts by mass of isobutanol and 18 parts by mass of block copolymer (B-1) were added, and 30 ° C. And stirred for 8 hours to uniformly dissolve the block copolymer (B-1). Next, 0.15 parts by mass of t-hexylperoxyisopropyl monocarbonate and 0.2 parts by mass of n-dodecyl mercaptan were added and dissolved uniformly. Nitrogen expelled oxygen in the reaction system. Polymerization was carried out at 115 ° C. for 3 hours. The reaction solution (1) was collected from the collection tube. The polymerization conversion measured by gas chromatography was 60% by mass.

  Next, 0.015 parts by mass of n-butyl-4,4-bis (t-butylperoxy) valerate was added to the reaction solution (1) and polymerized at 130 ° C. for 3 hours. The polymerization conversion rate measured by gas chromatography of the obtained reaction liquid (2) was 90 mass%.

Next, the reaction liquid (2) was heated to 220 ° C. and continuously supplied to a twin-screw extruder, and volatile components mainly composed of unreacted monomers were separated and removed at 250 ° C. A repeating unit derived from n-butyl acrylate is added to 52 parts by mass of a methacrylic resin (A) composed of 95% by mass of repeating units derived from methyl methacrylate and 5% by mass of repeating units derived from methyl acrylate. Pellet methacrylic compound containing 48 parts by mass of a block copolymer (B-1) having a polymer block (a) comprising a polymer block (b) comprising a repeating unit derived from butadiene as a dispersed phase A system polymer composition was obtained. The residual volatile content was 0.2% by mass. The pellet-like methacrylic polymer composition was evaluated by the above method.
The evaluation results are shown in Table 2.

<Example 2>
Except for changing the block copolymer (B-1) to the block copolymer (B-2), in the same manner as in Example 1, 95% by mass of repeating units derived from methyl methacrylate and derived from methyl acrylate The polymer block (a) consisting of repeating units derived from n-butyl acrylate and the repeating units derived from butadiene are present in 52 parts by mass of the continuous phase consisting of methacrylic resin (A) consisting of 5% by mass of repeating units. A pellet-shaped methacrylic polymer composition comprising 48 parts by mass of a block copolymer (B-2) having a polymer block (b) as a dispersed phase was obtained. The residual volatile content was 0.2% by mass. The pellet-like methacrylic polymer composition was evaluated by the above method. The evaluation results are shown in Table 2.

<Example 3>
13 parts by mass of methyl methacrylate, 1 part by mass of methyl acrylate, 30 parts by mass of toluene, 30 parts by mass of isobutanol, and 26 parts by mass of block copolymer (B-2) were added to an autoclave with a stirrer and a sampling tube. The mixture was stirred at 0 ° C. for 8 hours to uniformly dissolve the block copolymer (B-2). Next, 0.15 parts by mass of t-hexylperoxyisopropyl monocarbonate and 0.1 parts by mass of n-dodecyl mercaptan were added and dissolved uniformly. Nitrogen expelled oxygen in the reaction system. Polymerization was carried out at 115 ° C. for 3 hours. The reaction solution (1) was collected from the collection tube. The polymerization conversion measured by gas chromatography was 50% by mass.

  Next, 0.015 parts by mass of n-butyl-4,4-bis (t-butylperoxy) valerate was added to the reaction solution (1), and polymerization was performed at 140 ° C. for 3 hours. The polymerization conversion rate measured by gas chromatography of the obtained reaction liquid (2) was 80 mass%.

  Next, the reaction liquid (2) was heated to 220 ° C. and continuously supplied to a twin-screw extruder, and volatile components mainly composed of unreacted monomers were separated and removed at 250 ° C. A repeating unit derived from n-butyl acrylate is added to 30 parts by mass of a methacrylic resin (A) consisting of 95% by mass of repeating units derived from methyl methacrylate and 5% by mass of repeating units derived from methyl acrylate. Pellet-shaped methacrylic compound containing 70 parts by mass of a block copolymer (B-2) having a polymer block (a) comprising a polymer block (b) comprising a repeating unit derived from butadiene as a dispersed phase A system polymer composition was obtained. The residual volatile content was 0.2% by mass. The pellet-like methacrylic polymer composition was evaluated by the above method. The evaluation results are shown in Table 2.

<Comparative Example 1>
To an autoclave with a stirrer and a sampling tube, 21 parts by mass of methyl methacrylate, 1 part by mass of methyl acrylate, 60 parts by mass of toluene and 18 parts by mass of block copolymer (B-2) were added and stirred at 30 ° C. for 8 hours. The block copolymer (B-2) was uniformly dissolved. Next, 0.15 parts by mass of t-hexylperoxyisopropyl monocarbonate and 0.2 parts by mass of n-dodecyl mercaptan were added and dissolved uniformly. Nitrogen expelled oxygen in the reaction system. Polymerization was carried out at 115 ° C. for 3 hours. The reaction solution (1) was collected from the collection tube. The polymerization conversion measured by gas chromatography was 60% by mass.
Next, 0.015 parts by mass of n-butyl-4,4-bis (t-butylperoxy) valerate was added to the reaction liquid (1), and polymerization was started at 130 ° C. When 1 hour had passed, the stirrer was torque over. Stopped and can no longer continue manufacturing.

<Comparative Example 2>
To an autoclave with a stirrer and a sampling tube, 21 parts by mass of methyl methacrylate, 1 part by mass of methyl acrylate, 30 parts by mass of toluene, 30 parts by mass of isobutanol and 18 parts by mass of a block copolymer (B-2) were added, and 30 ° C. And stirred for 8 hours to uniformly dissolve the block copolymer (B-2). Next, 0.15 parts by mass of t-hexylperoxyisopropyl monocarbonate and 0.2 parts by mass of n-dodecyl mercaptan were added and dissolved uniformly. Nitrogen expelled oxygen in the reaction system. Polymerization was carried out at 115 ° C. for 3 hours. The reaction solution (1) was collected from the collection tube. The polymerization conversion rate by gas chromatography was 60% by mass.

  Next, the reaction solution (1) was heated to 220 ° C. and continuously supplied to a twin-screw extruder, and volatile components mainly composed of unreacted monomers were separated and removed at 250 ° C. Polymer block consisting of 42 parts by mass of a methacrylic resin (A) consisting of 95% by mass of repeating units derived from methyl methacrylate and 5% by mass of repeating units derived from methyl acrylate, and repeating units derived from n-butyl acrylate A pellet-shaped methacrylic polymer composition having (a) and 58 parts by mass of a block copolymer (B-2) having a polymer block (b) composed of repeating units derived from butadiene was obtained. A dispersed phase comprising the block copolymer (B-2) was not formed. The residual volatile content was 0.2% by mass. The pellet-like methacrylic polymer composition was evaluated by the above method. The evaluation results are shown in Table 2.

<Comparative Example 3>
Using pellets of a polymer composition in which 90 parts by mass of core-shell polymer particles containing 70% by mass of a styrene-butyl acrylate random copolymer rubber having a particle size of 0.1 μm were mixed with 10 parts by mass of a methacrylic resin, By the same method as in Example 1, a molded product having a thickness of 3 mm and a molded product having a thickness of 1 mm were produced by injection molding to obtain a test piece for evaluation. Flexibility is 70, tensile strength is 12 MPa, tensile elongation is 200%, haze is 2.0%, warm water whitening resistance is 26.8%, film formability is ○, laminate moldability is ○, and film appearance evaluation is × The low-temperature bendability (20 ° C./−20° C.) of the laminated product was ○ / ×.

  From the results of Table 2, the polymer block (a) consisting of repeating units derived from (meth) acrylic acid alkyl ester is added to the continuous phase consisting of methacrylic resin having 50% by mass or more of repeating units derived from methyl methacrylate. A polymer composition (Examples 1 to 3) in which a block copolymer (B) having a polymer block (b) composed of repeating units derived from a conjugated diene compound is dispersed is shown in Comparative Example 2 or 3. In comparison, it can be seen that while maintaining flexibility, it is excellent in appearance (low irregularity), transparency, hot water whitening resistance, low temperature characteristics, and film forming properties.

  According to the present invention, while maintaining the features such as good moldability, beautiful appearance, high transparency, and excellent weather resistance inherent in methacrylic resins, flexibility, appearance (low gloss), transparency, warm water whitening resistance A methacrylic polymer composition having excellent properties is provided. The methacrylic polymer composition includes signboard parts, display parts, lighting parts, interior parts, building parts, transport equipment parts, electronic equipment parts, medical equipment parts, equipment related parts, optical related parts, traffic related parts, building materials, It can be applied to a member for home appliances.

Claims (9)

  Polymer block (a) consisting of repeating units derived from (meth) acrylic acid alkyl ester and conjugated diene compound in continuous phase consisting of methacrylic resin (A) having 50% by mass or more of repeating units derived from methyl methacrylate The block copolymer (B) having a polymer block (b) composed of repeating units derived from the above is contained as a dispersed phase, and the block copolymer (B) with respect to 100 parts by mass of the methacrylic resin (A). Is a methacrylic polymer composition that is more than 80 parts by mass and not more than 300 parts by mass.   The methacrylic polymer composition according to claim 1, wherein the block copolymer (B) is a star-shaped block copolymer.   The star block copolymer is composed of arm polymer blocks, and the polystyrene-reduced number average molecular weight calculated by gel permeation chromatography (GPC) is expressed by the formula: [number average molecular weight of star block copolymer]> 2. The methacrylic polymer composition according to claim 2 satisfying x [number average molecular weight of arm polymer block]. Star block copolymer has the chemical structural formula:
(Polymer block (b) -polymer block (a)-) _n X
The methacrylic polymer composition according to claim 2 or 3, wherein X is a coupling residue, and n is a number exceeding 2.   The methacrylic polymer composition according to any one of claims 1 to 4, wherein the (meth) acrylic acid alkyl ester is an acrylic acid alkyl ester.   The methacrylic polymer composition according to any one of claims 1 to 4, wherein the (meth) acrylic acid alkyl ester contains n-butyl acrylate.   The methacrylic polymer composition according to any one of claims 1 to 6, wherein the conjugated diene compound contains 1,3-butadiene.   The block copolymer (B) comprises 30 to 65% by mass of a polymer block (a) having a glass transition temperature of 23 ° C. or less and 35 to 70% by mass of a polymer block (b) having a glass transition temperature of 0 ° C. or less. The methacrylic polymer composition according to claim 1, which has a refractive index of 1.48 to 1.50.   A molded article comprising the methacrylic polymer composition according to any one of claims 1 to 8.